Keeping you up-to-date on hydraulic cylinders & components

Hydraulics 101: What is the Bore of a Hydraulic Cylinder?

Sometimes we talk about things in a way that makes perfect sense to us, forgetting that it may not make a lot of sense to people that are not “in the business” of our industry. So I’m starting this new series of posts for those new to hydraulics & hydraulic cylinders in particular. We will try to keep the posts short, to the point, easy to understand & informative.

So, what is the “Bore” of a hydraulic cylinder & why is it important?
The bore is simply the INSIDE DIAMETER of the tube of the cylinder.

The Bore of the cylinder determines the total power of the cylinder. The larger the bore, the more it can lift or push. If you see or hear us talking about a “4 inch” cylinder, we are always talking about the bore of the cylinder. The outside diameter (OD) is usually about 1/2″ larger than the bore, but it depends on the wall thickness, so if you measured your cylinder from the outside and it measures 4-1/2″, you can be pretty sure its a 4″ Bore cylinder.

WoW,,, Wow Hydraulics 101!!! I can’t wait to tell my 2 brothers and friends,, You guys have provided me a learning tool I’ve been looking for for at least 20 years…
I just discovered your site yesterday, and haven’t even got to read much,, but I’m so happy to have found You and especially Hyd. 101, that I just had to let you know how happy I am to have this information available to me !!
Very Sincerely Jack Marks in Pennsylvania!!

I don’t know about some of your other readers, but sometimes I confuse the bore with the stroke of a hydraulic cylinder. This information helped to clear up the difference between the two. I guess I just have to think of the bore of a hydraulic cylinder as the inside diameter of the tube that determines how much power it can push, and the stroke as the distance the cylinder can travel. Thanks for clearing that up!

Thanks for explaining what a bore hole is in hydraulics. A friend of mine drills wells for a living, and he talks about the “bore” quite a bit when we ask him about work. It’s making a lot more sense now that I know what it is. Thanks for sharing!